How Do Exit Polls Work? Find Out Here

ABC News is conducting exit polls in 31 primary races on Super Tuesday, along with polling partners CBS, CNN, Fox, NBC and the Associated Press. On election days, exit polls remain the best source of information about who voted, for whom they voted, and why. Here are answers to some frequently asked questions about exit polls:

What are they?

Exit polls are surveys conducted as voters exit their polling place on Election Day. Reaching voters at that moment is important because it overcomes the problem pollsters have conducting telephone polls: people tend to misreport whether they voted or not. The "who won and why did they win" coverage on election night comes mainly from exit poll results, with the information reaching most Americans by television, and increasingly by the internet.

How are exit polls conducted?

Interviewers stand outside polling places in randomly selected precincts. They attempt to interview voters leaving the polling place at specific intervals (every 4th or 10th voter, for example). Voters who participate fill out a paper questionnaire, and place it in a box. Interviewers phone in results several times during the day. When a voter refuses to participate, the gender, approximate age and race of that voter are noted. In this way, the exit poll can be statistically corrected to make sure all voters are fairly represented in the final results.

What sorts of questions are asked in an exit poll?

Most importantly, exit polls ask for whom the voters cast their ballot, but they also gather demographic information to determine whether differences in such things as income, age, race, gender, and education impacted voting patterns. Typically, the exit poll also questions the voter's position on issues that were important in the race.

Are exit polls accurate?

Exit polls, like any other survey, are subject to sampling errors. Before news organizations report any exit poll results or make projections, though, they compare results to pre-election polls, past precinct voting history, and have statisticians and political experts carefully review the data. Actual vote count is added in throughout the evening and becomes particularly important in the closest elections.

How do the exit polls account for the people who vote by mail?

In the last national election, nearly 22% of Americans voted before Election Day. In states with high numbers of absentee voters, telephone interviews are conducted to reach and survey those voters. Information from those telephone interviews is included in the final exit poll results.

When will exit poll results be reported?
There is a strict quarantine on any news coming from the early waves of exit poll data until 5:00 p.m. ET. Also, the news organizations do not project winners in any state until after the polls have closed. Poll closing times are available on ABCNews.com. By late afternoon (approximately 5:45 p.m. ET), some initial demographic data about voter turnout will be available on ABCNews.com. That information will be constantly updated throughout the evening.